Filter



FIG. 1 is a front side perspective view of a filter showing my new design;

FIG. 2 is a top plan view thereof; and

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a front elevational view thereof;

FIG. 5 is a side elevational view thereof; and,

FIG. 6 is a back elevational view thereof opposite to that shown in FIG. 4. 

The ornamental design of a filter, as shown and described. 